Tracer for automatic two-dimensional follower control



Oct. 17, 1961 F. MOORE 3,004,747

TRACER FOR AUTOMATIC TWO-DIMENSIONAL FOLLOWER CONTROL Original Filed 000. 19, 1956 5 Sheets-Sheet 1 IN VEN TOR.

PIP INA MOO/FF Oct. 17, 1961 F. MOORE 3,004,747

' TRACER FOR AUTOMATIC TWO-DIMENSIONAL FOLLOWER CONTROL Original Filed Oct. 19, 1956 5 Sheets-Sheet 2 WWW mmk

W36 SQC VEQ TUNE T64 yw ru ssia rso TRACER FOR AUTOMATIC TWO-DIMENSIONAL FOLLOWER CONTROL 11 7- 4- INVENTOR.

n/am Oct. 17, 1961 F. MOORE 3, ,747

TRACER FOR AUTOMATIC TWO-DIMENSIONAL.- FOLLOWER CONTROL Original Filed Oct. 19, 1956 5 Sheets-Sheet 5 I TEMPLATE.

66 TAAcEn. SPINDLE uvvsuroa F7717? M00196 BY rman TRACER FOR AUTQMATIC TWO-DIMENSIONAL FOLLOWER CONTROL Frank Moore, Detroit, Mich, assignor to Manuel Turchan, Dearhorn, Mich.

Original application Oct. 19, 1956, Ser. No. 617,052, now Patent No. 2,891,384, dated June 23, 1959. Divided and this application Oct. 3, 1957, Ser. No. 688,662

6 Claims. (Cl. 251-3) This is a division of my co-pending application, Serial No. 617,052, filed October 19, 1956, now Patent No. 2,891,384.

This invention relates to an automatic two-dimension follower control by tracer deflection angle, and more particularly to an automatic control mechanism for use in conjunction with a duplicating device whereby the tracer responds to the profile of a template as it traverses said template and automatically controls relative movements between a pair of right angularly related slides and a cutting tool on one of said slides produces in a workpiece a shape exactly corresponding to said profile.

It is the object of this invention to provide. a novel tracer construction, which not only includes a moveable valve responsive to deflections of the tracer spindle, but also includes a series of electrical switches providing automatic control for switching tracer control from one of two right angularly related slides, to the other, and switching constant feeding from such other slide to said first slide.

It is a further object of this invention to provide an electrical system in conjunction with a fluid control system whereby the angle of deflection of the tracer as it responds to the contour of the template will provide an automatic control for the tracer and for a cutter associated therewith for movement in unison for automatically reproducing in a workpiece the contour of a template throughout 180 or 360 degrees. 7

These and other objects will be seen from the following specification and claims in conjunction with the appended drawings in which:

FIG. 1 is a vertical section of the present tracer.

FIG. 2 is a section on line 2-2 of FIG. 1.

FIG. 3 is a hydraulic diagram for the present invention.

FIG. 4 is a portion of the electrical diagram for the present invention.

FIG. 5 represents another portion of the same electrical diagram.

FIG. 6 is a diagrammatic view illustrating various positions of the tracer and associated switches and its deflection angles with respect to a 180 degree template.

FIG. 7 is a similar diagrammatic view wherein the tracer traverses the template profile throughout 360 degrees.

FIG. 8 is a diagrammatic view of the switch arrangement thereof.

It will be understood that the above drawings illustrate merely a preferred embodiment of the invention and that other embodiments are contemplated within the scope of the claims hereafter set forth.

Referring to the drawings, FIGURES l and 2 illustrate the preferred construction of the tracer employed in the present invention.

The tracer consists of a hollow body 11 with a ported valve sleeve 12 secured therein and including a depending threaded annular flange 13 projected down into the threaded hub 14 of the transverse switch body 15.

Said body includes a depending threaded flange 16 projected down into the threaded upper end of barrel 17 within which is axially positioned the elongated spindle 18. The spindle projecting below said barrel terminates in stylus 19, and intermediate its ends is supported upon 3,004,747 Patented Oct. 17, 1961 ice the race 20 of the bearing 21 which is biased downwardly within said barrel by spring 22, and adjustably supported within said barrel by the nut 23, and secured by lock nut 25. A suitable clearance is provided at 24 between said spindle and adjusting nut whereby the spindle is free for universal tilting movements with respect to this hearing support as the stylus 19 traverses and responds to the profile of a template, hereafter described.

Cup 26 is loosely positioned around the lower end of barrel 17 and centrally secured at 27 to spindle 18. The axial cone shaped notch 28 at the upper end of the spindle supports ball 29 upon which rests the vertically movable valve 30 which has formed therein a series of annular grooves 31, 32 and 33.

The control stem 34 at its lower end is secured axially to valve 30 and at its upper end on the exterior of cap 37 has a disc 35 secured thereon to permit manual longitudinal adjustment of valve 30, should this be desired.

Stem 34 projects loosely through hollow adjusting nut 36 which is threaded down into hollow cap 37, whose lower end portion 38 has a flange 39, in turn threaded down into stationary sleeve 12.

Disc 40 is secured upon stem 34 below nut 36, and intermediate said disc and the upper end of said nut there is provided coiled spring 41 adapted to normally urge the valve and spindle downwardly into what is called a negative position of the valve, FIG. 1, and which would correspond to the position the valve would take when the stylus 19 is put out of contact with the template.

The extent of valve adjustment is approximately two to of an inch. In the operation of the tracer the valve will assume an intermediate neutral position slightly above the position shown in FIG. 1 when the stylus is brought into initial contact with the template. In such neutral position pressure fluid supplied to the tracer at port P may enter opening 31, but is blocked from passage either into cylinder ports C1 or C2.

In the negative position of the valve, FIG. 1, above mentioned, such pressure fluid will pass from opening 31 into cylinder port CI for direction to one end of a cylinder; and the exhaust from said cylinder returns through cylinder port C2 and into valve opening 32 and out through exhaust port X.

Should the stylus in traversing the profile of the template reach a rise or projection therein, the valve, due to the universal mounting of the spindle, will be projected upwardly slightly above said neutral position so that pressure fluid in opening 31 will be directed through cylinder port C2 to the opposite end of the cylinder. At the same time exhaust from the cylinder returns through cylinder port C1 and valve opening 33 for return to the fluid storage sump through exhaust port X.

Cam 42 is arranged slightly below disc 40 and is mounted upon rotatable shank 43 having right angularly arranged handle 44. Should the stylus be out of contact with the template the tracer valve 30 may be manually controlled by rotation of cam 42 until it supportably engages disc 40 for controlling vertical adjustments thereof.

For example, should the operator desire to stop inward feeding due to the negative position of valve 30, this can be doneeasily by rotation of cam 42 lifting the valve to a neutral position. Further lifting of the valve manually will cause a reversal of the fluid connections to the cylinder under tracer control, and cause relative outward feeding.

Disc 45 is secured upon stem 34 adjacent the lower end of cap 37 and is in contact with the reciprocal plunger 46 of the governor switch or safety limit switch 47 secured within said cap at 48 and including a pair of electrical connections 49 for breaking the electrical circuit within the tracer, should at any time there be an exces- Electrical circuits Referring to the electrical diagram shown in FIGS. 4, 5 and 6, in addition to in limit switch 66, right limit switch 65 and left limit switch 67 above described in connection with FIG. 2, there is shown a fourth out" limit switch 100 whereby the present tracer is adapted for traversing the profile of a template throughout 360 degrees as shown in FIG. 7.

Line 103 interconnects ll-volt 60 cycle power lines 101 and 102 with normally open start trace button or switch 104, and in cooperation with a second normally closed stop trace" switch 105, for energizing the #1 control relay which may be referred to as ICR, and in a like manner the remaining control relays as ZCR, 3CR, etc.

In parallel circuit with starting switch 104 there is provided a normally closed safety governor switch 47 and a normally open contact ICR of #1 contact relay. A second normally open contact ICR is also provided in power line 101.

The lead 106 between lines 101 and 102 includes #2 control relay and the normally open trace in switch 122. There is a branch from lead 106 connecting one of the contacts of the normally open in limit switch 66. Lead 107 including #3 control relay connects one of the normally open contacts of the right limit switch 65 with power line 102. A separate lead 123 connects the other contact of limit 65 with line 101. Branch 107, from #3 control relay is joined to power line 101 with the normally open trace righ switch 126 interposed.

'- Lead 108 connects one contact of left limit switch 67 with power line 102 and with #4 control relay interposed. The other contact of limit switch 67 is connected with power line 101 by lead 123. Branch line 108 interconnects one contact of limit switch 67 and powerline 101, and interposed therein the normally open trace left switch 124.

' Circuit 109 including #8 control relay connects one contact of out limit switch 100 with powerline 102. The other contact of switch 100 connects powerline 101 through lead 123. Lead 109 is also connected with powerline 101 with normally open trace out switch 125 interposed.

' Branch line 123 connects powerline 101 with the one contacts of each of the four limit switches 66, 67, 100 and 65. The other contacts of the limit switches are respectively connected to one of the control relays 2, 3, 4 and 8.

Lead 110 which includes #5 control relay interconnects powerlines 101 and 102 and includes in series normally open contacts 20R and normally closed contacts 60R, 70R and 9CR of the respective control relays 2, 6, 7 and 9.

Holdling circuit 111 for #5 control relay is connected with lead 110, and also interconnects powerlines 1 and 102 and includes the pilot light 118 which indicates the tracer operation when energized i.e., feed left trace in.

Circuit 111 includes normally open contacts 50R and normally closed contacts 3CR, 4CR and 8CR, forming respectively parts of the control relays 5, 3, 4 and 8.

Lead 112 connects #6 control relay with powerlines 101 and 1102, and interposed in series are the normally open contacts 3CR and normally closed contacts SCR,

7CR and 9CR forming a part of the respective control relays 3, 5, 7 and 9.

The holding circuit 113 for control relay #6 connected with lead 112 and also interposed between lines 101 and 102, includes the pilot light 119 which indicates that with #6 control relay energized the feed is in" and tracing is to the right. Line 113 includes normally open contacts 6CR and normally closed contacts 20R, 4CR and 8CR of the respective control relays 6, 2, 4, and 8.

Lead 114 connecting #7 control relay with the powerlines includes normally open contacts 4CR and normally. closed contacts SCR, 60R and 9CR of the corresponding control relay switches. pilot light indicating trace left and feed Tout also includes normally open contacts 7CR and the normally closed contacts 20R, 30R and 8CR of the corresponding.

control relays.

Circuit 116 connects the powerlines with #9 control relay and includes normally open contacts 8CR and normally closed contacts 50R, 6CR, 7CR from the corresponding relays. The holding circuit 117 for pilot light 121 on energization of the #9 control relay includes normally open contacts 9CR and normally closed contacts 20R, 3CR and 4CR of the corresponding control relays. Pilot light 121 designates trace out and feed right."

In conjunction with the various pairs of solenoids for each direction valve, FIG. 3, there are additional branch lines in FIG. 5 which interconnect the powerlines with said solenoids. Circuit 127 includes the normally open contacts SCR and trace in solenoid 89. Lead 128 provides power to trace out solenoid 90 on closing of normally open contacts 9CR from the corresponding relay switch.

Lead 129 through the normally open contacts 6CR provides power to the trace right solenoid 86; and lead 130 provides power through normally open 7CR to the trace left solenoid 85.

Simultaneously with the energizing of one trace controlling solenoid there will be an energization of one feed controlling solenoid. For example, in FIG. 5 lead 131 provides power to feed left solenoid 98 through another normally open contact SCR, i.e., when number 5 relay is energized both solenoids 89 and 98 are activated.

Lead 132 provides power to feed right solenoid 99 through another normally open contact 9CR at the same time as trace out solenoid 90 is activated.

Circuit 1313 provides power to feed in solenoid 96 upon energization of #6 control relay and closing of the normally open contacts 6CR. Circuit 134 provides power to solenoid 97 upon closing of the normally open contacts 7CR of the #7 control relay.

In conjunction with constant feeding under the control of solenoids 96, 97, 98 and 99 there is interconnected in their respective circuits a normal feed, stop and reverse selector switch 135, with respective interconnecting branch lines 136, 137, 138 and 139, FIG. 5, whereby changing the switch from the position shown to the second position will etfect a reversal of the operation produced by the energizing of the feed controlling solenoids 96, 97, 98 and 99. An intermediate position of switch 135 cuts off all feeding.

For example, in normal operation with the selector switch 135, as shown in FIG. 5 relative movement of spindle 18 in FIG. 7 with respect to template 140 will be in a counter clockwise direction. On operation of the selector switch to its second position, there will still be an automatic traverse of said template, in the reverse direction.

Referring to FIG. 7, template 140 has an internal profile 141 and there is diagrammatically shown a series of numbered and angular positions 1 through 8 of the tracer spindle 18 as the stylus 19 traverses in a counter clockwise direction said profile. The deflection angles Holding circuit 115 including V Deflec Limit SW Tracer Nor. Feed Template Position tion Closed Seeks Direc- Angle tion 1 90 Left. 2 136 Left. Betw 137 Out. 180 Out. 225 Out. 226 Right 270 Right 315 Right Betwee 316 In. I11. 8 45 In. Between 8 and '1. 46 Lett.

Set out herebelow is a schedule also on the same as ap plied to 180 degree tracing between positions 1-9 of FIG. 6.

Position tion Limit Switch Tracer Feed Angle, Closed Seeks D recdegrees l71011 6- gietween 6 and 7.

Operation Assume the follower is in start position, FIG. 6, and the pumps, FIG. 3, are running and developing fluid pressure. With trace metering and feed metering valves 80 and 95 closed, depress start trace button 104, FIG. 4, energizingth-roughlead 103 1 control relay (ICR) whose normally open contacts (ICR) close to seal (ICR) and energize the tracer control circuit. ICR is sealed or .held through the normally closed contact of the governor or safety limit switch 47 on the tracer. The governor or safety limit switchon the tracer opens its normally closed contact on over-deflections of the tracer through disc 45,. plunger 46,. FIG. 1, to unseal ICR thus de-energizing the tracer control circuit to stop all-trace and feed movements and prevent damage to workpiece and machine; With ICR sealed depress trace in button 122, FIG. '4, energizing through lead 106, ZCR whose normally open contact incircuit- 110 closes energizing SCR through normally closed contacts of 6CR, 7CR and 90R. 56R is sealed in by one of its normally open. contacts, circuit 111 through normally closed contacts of SCR, 40R and 8CR so that when the trace in button is released de-energizing 26R, SCR remains energized. The trace in-feed left pilot light 118 is energized along with CR=to give visual indication of tracer operation.

Another normally open contact of SCR circuit 127, FIG. 5, closes energizing trace in solenoid 89 while a third normally-open contact of SCR circuit 13-1 energizes the feed left solenoid 98 (feed-jnormaLstop, reverse selector switch 135 is shown in normal position).

Whenthe trace s9 and iced "tea" as solenoids are energized, the following hydraulic action takes place in FIG. 3. Fluid from the tracer pump passes through conduit 75 to the pressure (-P) port of the tracer valve 30. The tracer spindle 18 and 19 (being away from the template), FIG. 6,- is undeflected at this time so the tracer valve spool 30, FIG. 1 is urged by its spring 41 to take the position shown on the schematic view, FIG. 3, and in FIG. 1, which directs the fluid from port P to port C1 of the tracer valve.

Conduit C1 carries the fluid from port C1 to the longitudinal trace direction valve 77, both solenoids 85 and 86 of which are deenergized at this time so that the fluid 7 passes through this valve and on through conduit 148 to the cross trace direction valve 78 whose trace in" solenoid 89 is energized causing its spool to direct the fluid into the conduit 87 connecting with the cross cylinder 71 in port.

The cross cylinder moves inwardly carrying the tracer l1 suitably mounted on slide 73 toward position 1 on the template, FIG. .6. Fluid being displaced from the out" port of the cross cylinder .is carried by conduit 88 to the cross trace direction valve 78 joined with C2 port of the tracer valve 30 from which it is directed to the tracer exhaust (X). port then into conduit 79 connecting with the trace metering valve 80.

The trace metering; valve is manually opened enough to give the desired speed of approach to the template and fluid passing through this valve is returned to the tank 74 through the tracer exhaust valve 81.

The cross cylinder 71- continues to carry the tracer 11 toward the template, FIG. '6, until the stylus 19 makes contact with the template causing the tracer spindle 18 g to be deflected inwardly position No. 1 (.at a-YQO deflection angle in this case) and displace the tracer valve spool so to neutral position thus stopping. cross cylinder movement by cutting ofi its-fluidflow. The trace metering valve isnow manually opened so that the tracer can take full control of the tracing slide 73.

The feed metering valve '95., FIG. 3, is now manually opened enough to give the desired feed rateand fluid from the feed pump passes through the cross feed direction valve 92 (its solenoids 96' and .97 are deenergized at this time) into the longitudinal feed direction valve 93 whose feed left solenoid 98 is energized to direct the fiuid to the left longitudinal cylinder port through conduit 82 causing the longitudinal cylinder 68 to move left" and carry the tracer 11 with it. Fluid being displaced from the right cylinder port is returned via conduit 83,. 94 to the tank through the longitudinal feed direction valve '93 and the feed metering. valve 95.

The tracer stylus follows along the path or profile .described by the template, FIG- 6, and since it is directly connected to the cross cylinder 71 through the cross trace direction valve 78, inward slopes of the templates resulting in negative spindle deflection displace the tracer valve spool St to cause fluid to be directed through conduit 87 to in port of the cross cylinder causing it to carry the tracer inwardly until the error is corrected and the tracer spool 30 returns to neutral (slightly above the position in'FIG. l) and. stops cross cylinder in movement. In like manner, outward slopes of the template result in positive spindle deflection which displaces the tracer valve spool to direct fluid through conduit 88 out port of the cross cylinder causing it to carry the tracer outwardly until the error is corrected causing the tracer spool to return to neutral and stop movement of the cross cylinder.

Returning to the electrical system, FIG. '4, when the stylus 1? contacts the template at point- 1 FIG. 6, the tracer spindle .18 tilts inwardly at a 90 deflection angle and the in limit switch 66 closes its contacts energizing 20R through leads 123, 106. Thisprepar'es for direc tion changes, but as 50K is already sealed-through cir--- cuit 111 having been energized when the trace in button 122 was depressed, no further action takesplace until point 2 is reached. p

' At point 2, the tracer spindle 18 tilts at a deflection angle of approximately 45, FIG. 6, so that both in and right limit switches 66, 65 close their contacts. This energizes SCR through lead 107 but since ZCR and SCR were previously energized, there is no further action until a location slightly beyond point 2 is reached where the' deflection angle of the tracer spindle becomes approximately 44 opening the in limit switch contact 66 but maintaining the right limit switch contact 65 closed.

a When the in limit switch contact opens, ZCR in circuit 106 is deenergized and since 3 CR remains energized (righ limit switch contact 65 closed) SCR is deenergized and drops out. This happens because the normally open contact of ZCR which was energizing SCR through the normally closed contacts of 6CR and 7CR and 9CR is now opened (2CR was deenergized) and the normally open contact of SCR which was holding through normally closed contacts of 3CR, ,4CR and SCR can no longer holdbecause normally closed SCR circuit 111 contact is open (SCR is energized).

When SCR drops out, solenoids trace in" 89 and feed left 98 and the trace in-feed left pilot light 118 are deenergized, and at. the same time the normally closed contact of SCR, which was preventing energization of 6CR by the normally open contact of SCR, closes and 6CR is energized and sealed. When 6CR is energized the trace right-feed in pilot light 119 is energized giving visual indication of tracer operation. Also normally open contacts of 6CR close and energize the trace right solenoid .86 and the feed inlsolenoid 96 (feed normal/stop/reverse switch 135 is normal position), FIG. 5.

The above changes in the electrical system result in the following hydraulic action. When the trace in" solenoid 89 is deenergized, the cross trace direction valve 78 springs to center position disconnecting the tracer cylinder ports from the cross cylinder ports. When the feed left solenoid 98 is deenergized, the longitudinal feed direction valve 93 springs to center position disconnecting the feed pump and feed metering valve 95 from the longitudinal cylinder ports. When the trace right solenoid 86 is energized, tracer cylinder 1 port is connected through conduit 83 to longitudinal cylinder 68 right port and tracer cylinder 2 port is connected through conduit 82 to longitudinal cylinder left port by. the shifting of the longitudinal trace direction valve spool 77. Energization of the feed in solenoid 96 shifts the cross feed directionvalve spool to connect the feed pump through conduit 87 with the cross cylinder in port and the feed metering valve 95 through conduit 88 to the cross cylinder out port. The result of this action is that the tracer takes control of the longitudinal cylinder 68 seeking right while a steady inward feed is applied to the cross cylinder 71. l

6 control relay remains energized and the trace rightfeed in action continues with the tracer maintaining contact between stylus and template by hydraulic control of the longitudinal cylinder location until position 4 is reached, FIG. 6.

At position 4, the deflection angle of the tracer spindle 18 becomes approximately 45 causing the contacts of both right and in limit switches .65 and 66 to be closed. At this point nothing other than energization of 20R occurs because 3CR and 0R were previously energized.

When the stylus 19 has moved to a position slightly beyond 4 where the deflection angle becomes approximately 46 the contacts of the right limit switch 65 open while those of the in" limit switch 66 remain closed. This deenergizes SCR whose normally open contact circuit 112 opens deenergizing 6CR andthe trace righ feed in pilot light 119.6CR is unsealed because its holding contact is in series circuit 113 with the normally closed 2CR contact which is open at this time because ZCR is energized. When 6CR drops out, its normally closed contact closes, allowing the normally open contact of ZCR to energize SCR and the trace in-feed left pilot light 118.5CR seals in on its normally open holding contact circuit 111 through normally closed contacts of SCR, 40R and SCR.

When 6CR is deenergized, its normally open contacts open de-energizing the trace right" 86 and feed in solenoids 96. When SCR is energized its normally open contacts close, energizing the trace in and feed left solenoids 89, 98. This transfers tracer control from the longitudinal cylinder 68 seeking right to the cross cylinder 71 seeking inwardly. It also transfers feed from cross cylinder in to longitudinal cylinder left.

The tracer stylus continues moving left, FIG. 6, and following the template by causing the cross cylinder to move in on inward slopes (negative deflection) and out on outward slopes (positive deflection).

When the stylus arrives at position 6, the deflection angle of the tracer spindle becomes approximately 135 causing the in and left limit switches 66, 67 to close their contacts energizing ZCR and 4CR. Since ZCR is energized first, SCR remains energized until the stylus moves to a point just beyond position 6 where the deflection angle of the tracer spindle becomes approximately 136 causing the in limit switch contact 66 to open, while the left limit switch 67 remains closed. This de-energizes 2CR whose normally open contact circuit in series with normally closed contacts of 6CR and 7CR, also 9CR opens deenergizing SCR and the trace in feed left pilot light 118.5CR is unsealed because its holding contact is in series circuit 111 with the normally closed 40R contact which is open at this time because 4CR is energized. When 5CR drops out, its normally closed contact closes, allowing the normally open contact of 4CR circuit 114 to energize 7CR and the trace left feed out pilot light 129. 7CR seals in on its normally open holding contact circuit 15 through normally closed contacts of ZCR, 3CR and SCR.

When SCR is deenergized its normally open contacts open deenergizing the trace in and feed left solenoids 89, 98. When 7CR is energized its normally open con tacts leads 130, 134, FIG. 5, close, energizing the trace left and feed out solenoids 85, 97. This transfers tracer control from the cross cylinder 71 seeking in to thelongitudinal cylinder 68 seeking left. It also transfers feed from longitudinal cylinder left to cross cylinder out.

The tracer stylus 19 continues to move out, FIG. 6, maintaining contact with the template by causing the longitudinal cylinder to move left on negative deflections and righ on positive deflections until position 8 is reached.

At position 8, the spindle deflection angle becomes approximately 135 causing the in and left limit switches 66, 67 to close their contacts. Since the left limit switch was previously closed, nothing other than energization of ZCR takes place until a point just beyond 8 is reached where the spindle deflection angle becomes approximately 134 opening the left limit switch contact 67 while the in limit switch contact 66 remains closed.

This degenerizes 4CR and since ZCR is energized, 7CR and the trace left-feed-out pilot light are degenerized while SCR and the trace in-feed left pilot light 118 is energized and sealed.

When 7CR is deenergized its contacts open, deenergizing the trace left 85 and feed-out solenoids 97. When SCR is energized its contacts close, energizing the trace in feed left solenoids 89, 98. This transfers 11 maintains contact with the template by causing the cross cylinder to move in on inward slopes (negative deflection) and out on outward slopes (positive deflection).

From the preceding explanation, it can be seen that this follower will trace the contour of a template or model in two dimensions, FIG. 6, and that it it is mounted on machine tool such as a lathe in spaced relation to a cutting tool so that the followers position relative to the template is the same as the cutting tools position relative to the workpiece the follower will guide the cutting tool in a path determined by the shape of the template or model to produce a workpiece whose contour is identical to that of the template or model.

This follower, which will trace in 3-directions, namely left, righ and in is ideally suited for application to maching tools of the lathe type. For application to machine tools of the milling machine type, FIG. 8, on which it would be necessary to trace in 4-directions namely, left, right, in and out, a follower of the same construction would be used with the addition of afourth limit switch 100 to be known as the on limit switch and mounted directly opposite the in limit switch 66, FIG. 4, so that outward deflections of the tracer spindle would result in the closing of the out limit switch contacts.

The out limit switch contacts are connected to operate an 8th relay circuit 109, FIG. 4, and contacts of the 8th relay are interlocked with contacts of SCR, 60R

and 'iCR so that a 9th relay circuit 116 together witha trace outfeed ri t pilot light 121 are energized in proper sequence when the tracer deflection angle was changing from approximately 225 degrees to approximately 226 point 4, FIG. 7. The contacts of the 9th relay, FIG. 5,.are connected to energize the trace on solenoid 90- (which is also shown on the'hydraulic diagram .FIG. 3) and the feed right solenoid 99 when the feed normal/stop/reserve selector switch .is in normal position as shown.

When the deflection angle changed from 31-5 degrees to 316 degrees point 6, FIG. 7, the condition of the out and right limit switch contacts 100, 65 would change from both closed to on open and righ closed resulting in deenergization of the 9th relay together with the trace "lout -feed right" pilot light 121 and the associated trace out feed right solenoids 90, 99 andenergization of the 6th relay, the trace right feed in pilot light 119 and the trace right 86 feed in 96 solenoids. A template and schematic view of the follower with 4 limit switches is shown in FIG. 7 and the schematic drawing of the electrical circuit used with this 4 limit switch follower is shown in FIGS. 4', 5, and 8. The hydraulic circuit for both types of follower is the same and is shown in :FIG. 3.

The selector switch 135 feed normal/stop/reverse is used .to reverse the progression around the template from left or counter clockwise when it normal position and to right or clockwise in the reverse position.

Referring to FIG. 4, the electrical tracing circuit may be energized initially by the trace in push button 122 as above described, where the stylus has the relative position shown in FIG. 6 with respect to the template. Should the stylus, however, be in such a position that the initial direction of tracer seeking would be to the left such as to position '7, FIG. 6, and with the stylus in position outwardly thereof, then the trace left button 124 would be pushed to energize the tracer circuit.

If it is desired, to trace out as from a central portion of template 140 to profile 141, then .the trace out button 125 would be activated. Alternately, if the stylus from a central position, FIG. 7, is to trace right button 126 is activated. The electrical tracing circuit may be de-energize'd at any time by pressing the stop trace button 105, FIG; 4.

Having described my invention, reference should now be had to the following claims.

I claim:

1. A tracer for an automatic control system comprising an upright body, a spindle universally mounted within said body and depending therefrom terminating in a stylus adapted to engage the profile of a template, an axially reciprocal fluid control valve in said body engagable with and responsive to deflections of said spindle, adapted for transmitting pressure fluid supplied to said body to one of two cylinder ports, valving means respectively connected to said cylinder ports adapted for selectively directing the pressure fluid under the control of said valve a series of right angularly related normally open limit switches in said tracer spaced around and from said spindle, one and a maximum of two adjacent limit switches being adapted toclose onangular deflection of said spindle responding to changes in template profile, adapted to control such valving means, a series of radial coplanar right angularly related limit switch operating shafts slidably mounted upon the tracer with their inner ends resiliently biased into engagement with'said spindle, a crossarm on the outer end of each shaft, and a contact on each arm normally engaging a corresponding limit switch contact.

2. A- tracer comprising an upright body, a spindle universally mounted within said body and depending therefrom terminating in a stylus adapted to engage the profile of a template, a series of right angularly related limit switches in said tracer spaced around and from said spindle, one and a maximum of two adjacent limit switches being adapted to close on angular deflection of said spindle responding-to changes in template profile, a series of radial coplanar right angularly related limit switch operating shafts slidably mounted upon the tracer with their inner ends resiliently biased into engagement with said spindle, a cross arm on the outer end of said shaft, and a contact on each arm normally engaging a corresponding limit switch contact.

.3. A tracer for an automatic control system comprising an upright body, a spindle universally mounted within said body and depending therefrom terminating in a stylus adapted to engage the profile of a template, an axially reciprocal fluid control valve in said body engageable with and responsive to deflections of said spindle, adapted for transmitting pressure fluid supplied to said body to one of two cylinder ports, valving means respectively connected to said cylinder ports adapted for selectively directing the pressure fluid under the control of said valve'a series of right angularly related limit switches in said tracer spaced around and from said spindle, one and a maximum of two adjacent limit switches being adapted to close .on angular deflection of said spindle responding to changes in template profile adapted to control said valving means.

4.Ihe tracer of claim 3, a series of separately operatable trace and feed control relays respectively connected with said limit switches whereby any of the following relay control conditions will alternately exist namely; trace in .feed left; trace rightfeed in; trace left feed-ou trace out feed.righ and an electrical circuit including a power source interconnecting said limit switches and control relays whereby the spindle through changes in the direction of its angular deflections in responding to the template profile automatically establishes one of the aforesaid control relay trace and feed conditions.

5. The tracer of claim 3, a series of alternately -operable pairs of trace and feed control solenoids, a series of separately operable control relays each respectively connected to a'limit switch and a pair of said solenoids whereby any of the following .solenoid control conditionswill' alternatelycxist namely: trace in feed left"; trace righ feed in{; trace left feed out; trace on feed right, and an electrical circuit including a power source interconnecting said limit switches and control relays whereby the spindle through chang in the direction of its angular deflections in responding to the tem'-" plate profile automatically establishes one of the aforesaid control solenoid trace and feed conditions.

, 6. The tracer of claim 3, a series of trace control and feed control solenoids arranged in alternately operable pairs, one trace and one feed control solenoid in each pair, a series of separately operatable control relays, each connected respectively to a limit switch, and to one of said pairs of solenoids, an electrical circuit connecting said limit switches, relay switches and solenoids and including a power source, each of said control relays having a plurality of normally open contacts connecting on energization one of said pairs of solenoids with said power source.

References Cited in the file of this patent UNITED STATES PATENTS 

